One of the most insidious
weapon systems ever conceived, the cruise missile is resurgent and as
it
appears will hold a significant place in the inventories of both the
Free World and the Communist Bloc. After its initial debut in the form
of the rudimentary but nevertheless deadly Fieseler V-1 the cruise
missile slumped into obscurity, restrained by accuracy and range
limitations imposed by the technology of the day.

The USAF's Strategic Air Command (SAC) toyed with Cruise
Missiles in the late fifties, but these were promptly discarded in
favour of the ballistic missile. The Russians had more faith in the
concept, developing a family of air launched weapons to arm the Bear,
Badger and Blinder bombers. The ultimate Soviet answer to the problem
was a fighter sized turbojet driven vehicle with a multi-Megatonne
nuclear warhead to achieve some sort of target kill probability, given
the limitations in the guidance system.

This entire family of weapons was really developed to support
the long range high altitude bomber, but as this delivery vehicle
became
less than viable due to advances in surface-to-air and air-to-air
missile (SAM/AAM) technology, the weapons it carried suffered a similar
fate (though it seems the Russians still maintain some of their earlier
types in service). Emphasis was shifted to low altitude penetration, as
evidenced by the deployment of the FB-111A, role revision of the B-52
and development of the B-1, protracted as it was.

But technology advanced and the Soviets did eventually
acquire
look-down/shoot-down capable fighters and this together with advances
in
radar capability meant that the geriatric B-52, SAC's primary weapon,
had little chance of successfully penetrating to heavily defended
targets deep in the USSR, to launch its SRAM short range nuclear
missiles.

The new B-1A bomber was to have assumed the B-52's role, with
a quoted 1/30 of the B-52's radar cross section, terrain following
capability and very high dash speed. But the mid seventies saw the
rebirth of the cruise missile, as inertial guidance, computer and
propulsion technologies reached a level of development which allowed a
new generation of these weapons. The Carter Administration, eager to
gain political mileage, dumped the manned B-1A bomber in favour of
rearming the B-52s with the new cruise missile.

Conceptually elegant, use an established platform to deliver
a
large load of missiles to the perimeter of the Soviet air defence
system, launch these in numbers sufficient to saturate the defences,
and
fly home. The missiles would enter Soviet territory, hugging terrain to
further reduce their very low detectability, eventually hitting their
preprogrammed targets with 200 kT nuclear warheads. The 1,500nm range
cruise missile would do away with the need to do the deep penetration
missions and thus allow retention of the existing B-52, saving on a new
fleet of expensive bombers.

In retrospect, it is apparent that the Carter administration
over estimated the true operational effectiveness of the weapon which
though useful could not, just as any single weapon cannot, provide all
the answers, so today we can see a revised B-1B in production to be
armed with a mix of the traditional SRAM missile and the new cruise
missile, flying a mission profile involving penetration and standoff
missile launches. The cruise missile itself has entered its next
generation in development, while still experiencing numerous teething
troubles, the Soviets respond ing in a two pronged exercise of
upgrading
their air defences with AEW and shoot-down capable air defence fighters
and deploying their bomber launched equivalent of the US' cruise
missile.

An AGM-86A ALCM (Air Launched Cruise Missile)
undergoing
final pre delivery tests at the Boeing plant. Probably the greatest
benefit of the cruise missile in time will be the financial drain it
has
caused the Soviet Union through having to develop a whole new family of
expensive counter measures to combat the threat, thus taking money away
from offensive programmes (US Air Force images).

The Boeing AGM-86B Air
Launched Cruise Missile (ALCM)

First of the cruise missile family to enter service and
essentially the only dedicated strategic weapon in the family, the
AGM-86B is a generic development of the early seventies Boeing SCAD
program. That vehicle subsequently developed into the AGM 86A, which
was
supplanted by the longer ranged AGM-86B which became the operational
version of the missile.

The Current AGM-86B is equipped with the basic TERCOM (Terrain
Contour Matching) inertial guidance system and this also reflects in
the
vehicle's mission profile. A TERCOM equipped vehicle will employ an
inertial navigation system (INS) to find its way to the target, however
the INS will accumulate a position error with time and this error must
be eliminated or reduced if the weapon is to have any sort of useful
accuracy. TERCOM does exactly that.

The TERCOM system uses a radar altimeter and barometric
altimeter to measure the profile of the terrain beneath the aircraft.
This information is then compared with stored terrain profile
information within the memory of the TERCOM computer to yield a
position
update. The update is then fed into the INS. The exercise of measuring
and matching the terrain profile is carried out only several times
during the weapon's flight, this provides sufficient accuracy while
limiting the size of the computer memory required to store the terrain
maps.

The missile is loaded with its position and a file of terrain
maps for its flight prior to launch, it is then fully autonomous. It
will hug terrain at several hundred to a thousand feet, following a
very
indirect flightpath through hostile territory, this serves to confuse
the defenders as to the exact nature of the target, alternately the
flight planner may route the flightpath to avoid known early warning
and
air defence facilities.

The AGM-86B is a 20ft 10.5 in (6.3m) vehicle weighing in at
3,1501b (1,420kg) at launch. Most of the airframe is occupied by the
four fuel tanks which feed the powerplant. That is a Williams
International F107 600 lb thrust class low bypass ratio turbofan,
weighing about 1501b (68kg) and occupying the last three feet of the
airframe. The engine mounts above the set of actuators for the
vehicle's
folding elevons, the tailpipe is shielded by a tailcone which
conceivably blocks infrared emissions from the engine hot end. The use
of a turbofan is advantageous in that it does provide better fuel
consumption than a turbojet, with a reduced infrared signature. The
penalty to be paid is in the thrust limitation, which will force the
vehicle to follow terrain with larger clearance (see June 1984 issue,
Terrain Following).

This tradeoff of signature vs thrust was presumably made in
the earlier phases of the weapon's development, when Soviet lookdown
radar capability was far lesser. It has since been identified as a
major
limitation in this weapon's penetration ability and is to be rectified
in a $300 million engine upgrade program which will provide a new
compressor, combustion system and ignition system. The result should be
a 40% thrust increase (SL) to improve terrain following performance in
the 100ft altitude region, a speed increase to 0.65 Mach and several
hundred miles of extra range.

Other than the powerplant, the tail region of the vehicle
also
houses a thermal battery and the small #4 fuel tank. The engine inlet
is
on the top of the fuselage, usefully shielded from GCI radars by the
airframe. The fuselage of the vehicle, from the rear propulsion section
to the forward payload/control section, is roughly equally split into
three fuel tanks, #3, #2, #1 from tail to nose. Prior to launch the
vehicle's wings, elevons and vertical stabiliser are stowed, they
deploy
upon release from the launch aircraft. The spine of the fuselage
carries
the control/instrumentation cables from the nose to the propulsion
section.

The instrumentation bay houses then the INE (Inertial
Navigation Element), Flight Controller and Radar Altimeter. Aft and
below the instrumentation bay is the payload bay, housing the W-80 200
kT nuclear device and its arming mechanism. The vehicle's nosecone
underwent modification in the early production phase, transitioning
from
the flattish shark nose to the rounded beluga nose, apparently to
reduce radar cross-section. In spite of the fact that the ALCM airframe
was not optimised for minimum radar signature, either in shape or
materials, it has a small cross section which will apparently be
reduced
by the use of stealth technologies in future upgrades. The USAF is also
considering the use of chaff and flare dispensers to further improve
survivability.

TERCOM
generates position fixes by sampling terrain height using a radar
altimeter, and then correlating the elevation profile against a digital
elevation map in the missile guidance system's memory. DSMAC performs a
correlation between a stored image and snapshot of the terrain beneath
the missile to generate a position fix (General Dynamics).

The radar altimeter
used to
generate elevation samples for TERCOM operation was designed to be
resistant to seasonal changes in the radar reflectivity of the terrain
(General Dynamics).

The ALCM Guidance System

The core of the ALCM's guidance system is the Litton LN-35
inertial navigation unit, built around a P-1000 inertial platform. The
P-1000 uses two dry tuned rotor gyros and three accelerometers (see
June
1984, AJQ-20 BNS, F-111C description for INS operation), the set has a
combined drift error rate of 0.6nm/hr (the drift error develops through
the combined inaccuracies in the gyro and accelerometer pickoffs,
mechanical tolerances friction and presumably also A/D quantisation
errors, and as such is intrinsic to all conventional inertial
platforms). The inertial set is complemented by a TERCOM computer and
Honeywell radar altimeter.

The radar altimeter, designed with power management,
minimised
sidelobes and variable PRF (pulse rate) for low detectability, is used
to generate a continuous stream of altitude readings. These are used
throughout the flight for terrain following, furthermore while the
missile is over a known mapped area, they are subtracted from the
barometric altimeter reading to generate terrain elevation readings.
The
mapped areas are stored as MxN matrices of point elevation readings
(further matrices) in the computer memory.

The terrain contour matching is then carried out by the
computer, which takes the series of height readings and uses a
mathematical algorithm to find the best fit of the
flightpath/position
in the matrix (map) and thus determines the position of the vehicle
with
some known (subject to the quality of the altimeters and maps) error.
This position information is then used to reduce the inertial set's
error.

To get the best possible update, the computer uses a technique
termed Kalman filtering. The Kalman filter is a mathematical algorithm
that, accounting for the INS errors and TERCOM matching errors with a
mathematical model, allows optimum mixing of the inertial set's reading
and the TERCOM system's reading.

Thus the Kalman filter will take readings from both systems
to
enable the calculation of a better position estimate, which is then
loaded into the inertial set. One of the nicer aspects of this
technique
is the fact that the algorithm apparently calibrates against the gyros,
as with each updating it gets a better and better idea of what the
particular gyros drift rates are. Furthermore, the matrices become
finer and finer in resolution as the missile nears its target.

Thus the TERCOM guided missile becomes more accurate the
closer it gets to the target (see Gelb A., Sutherland A.A.; Software
Advances in Aided INS, Navigation, Vol. 17, 70/71). As is intuitively
obvious, the TERCOM system performs best over rugged terrain and is
useless over ocean. In operation the ALCM would fly on inertial
guidance
between individual matrices, where it updates its position and changes
heading if required, therefore it is only really necessary to have a
series of well known rugged/unique areas which can be used as matrices.
Critics of the cruise missile have focussed strongly on the TERCOM
system. The first target was the radar altimeter, allegedly easy to
detect and jam. The second target was the software/system error.
Northern Siberia is very flat and covered with annually variable ice
therefore critics believe that uniqueness cannot be guaranteed.

The TERCOM system does have built in measures to deal with
fix
problems, specifically it will take three TERCOM fixes and check if at
least two of the three agree in position before it commits itself to an
update of the inertial set. Only if no agreement can be found will the
missile degrade down to pure inertial guidance, disarm itself and
function as a decoy, effectively.

One option under review as an alternative to TERCOM is the
use
of the Navstar Global Positioning System (GPS) L-band satellite
navigation system. GPS offers 15m positioning accuracy virtually
worldwide and would eliminate the need for a costly global mapping
exercise. On the other hand it can be jammed and many SAC commanders
are
apprehensive about the ability of the 18 satellite constellation to
survive the initial phases of a nuclear exchange, not to mention the
GPS
receivers coping with atmospheric phenomena and EMP effects. Two
Tomahawk cruise missiles have been fitted as testbeds for GPS, though
little has been published on test results to date [Editor's Note 2005: GPS was introduced
using a single channel receiver, it was replaced during the 1990s with
jam-resistant multi-channel receiver.].

Another option being developed at this stage is a Laser
Terrain Following Radar. Laser based radars have been tested in the
past, using eg C02 lasers and offer both precise narrow beam
pointing and precise range gating. The USAF funded development program
envisages the use of a high range resolution laser radar for cruise
missile terrain following, navigation and terminal targeting. Hughes
Aircraft are currently involved in the 42 month advanced development
phase for the system, General Dynamics will be providing a Tomahawk
flight test vehicle.

Each B-52G will carry 12 ALCMs externally and 8 more
on a
bomb bay mounted rotary launcher. The ALCMs only deploy their small
wings and tail when released from the launch aircraft. All 168 B-52Gs
will be AGM-86A armed while the eventual 100 strong B-1B force will
also
be equipped with this and the Advanced Cruise Missile (US Air Force).

Earlier demonstrations of laser radar have shown the ability
to easily resolve objects such as wires, power lines, telephone poles
and trees. With sufficiently powerful signal processing this
information
can be exploited both for very low level terrain follow ing, TERCOM and
target recognition from its geometry. Limitations may however exist due
to atmospheric absorption under some (eg water vapour laden)
conditions.

ALCM/Launch Vehicle Interface

The AGM-86B is currently carried by the Boeing B-52G bomber
and will also equip the Rockwell B-1 B bomber. The SAC B-52s carry
twelve ALCMs, six per underwing pylon and will eventually carry a bomb
bay mounted internal rotary launcher with another eight rounds. This
launcher, termed the CSRL (Common Strategic Rotary Launcher), is
compatible with ALCM, the current SRAM defence suppression missile and
the future ACM (stealth cruise missile) and AASM (Advanced Air-Surface
Missile, SRAM replacement). The B-1B will carry ALCM internally on its
CSRL and also externally, twelve rounds carried tangentially attached
beneath the fuselage; flanking the aft bomb bay, forward bomb bay and
flight deck access well. The Northrop ATB 'Stealth Bomber' will also be
fitted with the CSRL.

The ALCM/Launch vehicle interface is typified by the
installation being developed for the B-1B. The Boeing designed OAS
(Offensive Avionics System) is built around an IBM AP-101F 16-bit
computer, which ties into two Sundstrand data transfer units and the
ALCMs. The OAS will load the terrain matrices (up to twenty) into the
ALCM prior to launch, the IBM computer having the ability to
communicate
with each missiles LN-35 INS and computer to provide the OAS operator
with exact status information on each round.

Though currently limitations in the number of available
matrices apparently restrict targeting to a set of prebriefed targets,
SAC's eventual objective seems to be the ability to select targets at
will if necessary at the discretion of the launch aircraft crew. Once
the matrices and flightpath/target data have been loaded into the
missile, it is ready for launch. Once the launch aircraft reaches its
release point, the LN-35 is updated with the final position supplied by
the bomber's nav/attack and the missile can be launched.

Mission Profile

In the event of a SAC strike against the USSR, the ALCM armed
B-52Gs (later also B-52Hs) would scramble from continental US airbases
and head for the Russian coastline. Typical approach paths would be
over
the North Pole as the far North of Russia is sparsely populated and
thus
difficult to effectively monitor. The aircraft would cruise at high
altitude until several hundred miles from the Russian coastline, where
the large GCI radars come into play. To elude these, the B-52s would
descend to a low altitude and activate their ESM/ECM systems.

In theory this would allow them to approach to within 200nm
of
the coastline, where they would launch the ALCMs.

This tactic would certainly apply to attacks on targets
within
the Leningrad-Moscow-Kuybyshev-Sverdlovsk arc, with weapon release over
the Barents sea. Aircraft targeted for the
Sverdlovsk-Novosibirsk-Irkutsk zones, including the Abalokovo battle
management radar and ICBM fields, would presumably cross the Russian
coastline between the Taimyr Peninsula and Bering Straits, hitting PVO
and C3 installations on the way in, using SRAM missiles (200kT). They
would release their ALCMs over the Siberian landmass. One would presume
this attack profile would also apply to strikes on Far Eastern targets,
with a convenient approach over land mass rather than ocean.

The ALCMs would after launch, be it over ocean or land, head
for their initial matrix and update. The first matrix is very coarse
and
is quoted at 26nm, successive matrices are smaller and smaller, the
terminal matrices being described by some sources as a mere 1 nm wide.
The weapon would then zig-zag along from matrix to matrix, penetrating
deeper and deeper. Presumably it would avoid PVO defences and populated
areas, approaching its target from a bearing least convenient to the
defender and probably with little or no warning. Only 85% of
prospective
targets can be hit from offshore launch zones and it is certain that
many aircraft would be expected to penetrate. It was that limitation in
the weapon's range that prompted SAC to reinitiate the B-1B, which
would
upon introduction take over the penetration role, leaving the B-52 with
only the standoff launch role.

SAC intends to arm 168 B-52Gs with the ALCM and all B-1Bs,
though it is not clear at this stage how many of the B-52Hs may be
armed. As one can see, a full scale strike would present the Russians
with a sizeable headache, to the tune of several thousand terrain
following missiles.

The Russians have responded strongly, they have deployed the
new S-300P/SA-10 SAM, phased array air defence radars, the Il-78 / A-50
SUAWACS airborne early warning platform, the new MiG-31 Foxhound and
Su-27 Flanker fighters, both with lookdown radar and shootdown
missiles.
The vigour with which they have pursued the development of their AWACS
illustrates the importance they place upon the cruise missile. One
could
presume the ultimate goal would involve setting up an AEW barrier along
the Northern coast of European Russia, to hit launch platforms and
incoming missiles over the ocean, together with AEW cover for key
Siberian and European targets.

Another move involves the deployment of Russian ALCMs
[RKV-500/Kh-55], carried by the massive Blackjack bomber and the trusty
Tu-95 Bear, this is currently being countered by increased US deploy
ment of AWACS and F-15 aircraft from continental US bases.

Over-The-Horizon (OTH) radar and orbital infrared
surveillance
platforms are both currently under review as options for early
detection
of incoming cruise missile carriers, prior to handoff to the
AWACS/interceptors. Though the ALCM has had numerous teething troubles,
both in software (resulting in the recent flight tests over Northern
Canada serving to acquire calibration data on flat polar terrain
performance and Coriolis effect compensation) and in powerplant
performance, it is an effective system. Not every target will have the
optimum set of defences or the appropriately 'non-unique' terrain
profiles along its approach paths.

The current development of the General Dynamics ACM (Advanced
Cruise Missile) is bound to create further problems for the Russians.
This composite/polymer skinned/structured missile, equipped with a low
heat signature Williams International F112 engine will offer a 40%
range
increase over the ALCM, at a fraction of the ALCM's radar and IR
signature. Whether it will use TERCOM or GPS is not clear at this
stage,
it is though expected to carry extensive ECM and ECCM systems. The ALCM
achieved IOC in December 1982, production was cut in April 1983,
bringing the total to 1,700 rounds at $4.3 billion. SAC plans to
further
acquire 1,300 ACMs, with a projected IOC of 1989.

The deployment of the ALCM has had a considerable effect in
increasing the US' ability to hit the Soviet hinterland - deployment of
even partial defensive measures has cost the USSR considerably and if
continued is certain to further resources from offensive weapons
programs [Editor's Note 2005: it ultimately became a key factor in the
bankruptcy of the Soviet Empire].

The overall significance of the ALCM is however far lessened
when one considers also the effects of submarine and ground launched
theatre nuclear cruise missiles, weapons of comparable capabilities
with
very flexible modes of deployment.

These together with conventional derivatives of the cruise
missile family will be the subject of Part II.

Part IIConventional and Theatre Nuclear
Cruise Missiles

The resurrection of the cruise missile in the last decade has spawned a
diverse family of weapons, some of which are merely order of magnitude
improvements upon earlier systems, but some of which do represent
original and unique concepts in weapon system development.

The impact of this family of weapons has been and will
continue to be significant, as the USSR has little choice other than to
spend on advanced air defence and early warning facilities. It is
hardly
surprising therefore that the Soviets have engaged in an unprecedented
propaganda campaign to stop deployment of these weapons, as propaganda
is intrinsically cheaper than buying AEW/AWACS platforms by the dozen.

The vehicle central to this whole issue is the Tomahawk
cruise
missile or rather any one of its numerous derivatives. A very compact
missile, the Tomahawk lost to the AGM-86 ALCM in the USAF's quest for
an
air-launched strategic cruise missile, but instead picked up the
ultimately more significant roles of the Ground Launched Cruise Missile
(GLCM), the Sea Launched Cruise Missile (SLCM) and the joint USAF/USN
MRASM (Medium Range Air-Surface Missile).

The latter roles have in particular resulted in a series of
warhead/airframe/guidance derivatives which are certain to keep General
Dynamics', the prime contractor's and McDonnell Douglas', the guidance
subcontractor's, production lines running for some time yet.

The General Dynamics
AGM/BGM/RGM-109 Tomahawk

Developed in the seventies as GD's answer to the Boeing ALCM,
the Tomahawk although functionally similar to its competitor is
aerodynamically and structurally a very different beast. The Tomahawk
was designed from the very beginning to coexist with a naval
multimission environment, this reflects in the airframe shape and
structural modularity of the vehicle. These two attributes offered a
basing/role flexibility, albeit gained at the expense of flat-out
maximum speed, which not only secured the weapon's future in the naval
arena but also won it the role of the GLCM.

The basic Tomahawk is a 21 ft (6.4m) vehicle with a launch
weight in the 26001b (1200kg) class, subject to specific missile
version. The missile airframe is essentially circular in cross section
from nose to tail, with most of the structural modules being
cylindrical
in shape. The aftmost section of the Tomahawk is the tailcone, which
houses both the control surface actuators, these driving the four
symmetrical folding control surfaces, and the powerplant. Here is where
a difference does exist between the basic Tomahawk and its air launched
MRASM derivative. The baseline Tomahawk is fitted with a 600lb thrust
class low bypass ratio Williams International F107 turbofan, common
also
to the ALCM (see Sept TE, Strategic Cruise Missiles). As the Tomahawk
is
somewhat lighter than the ALCM, the thrust-to weight-ratio limitation
due to the use of this powerplant is not so apparent.

The MRASM missile is then fitted with a Teledyne CAE variable
speed turbojet, also 6001b class, somewhat thirstier but far cheaper
(cca 60%) than the turbofan.

The powerplant thrust line is depressed by several degrees
and
offset below the longitudinal axis of the missile. Forward of the tail
cone is the cylindrical aft body section of the weapon, it houses the
ventral engine inlet/inlet duct assembly in all versions. Prior to
launch the inlet is flush with the missile's skin, but deploys upon
reaching a programmed point in the launch sequence. In MRASM the upper
half of this section houses the TERCOM, INS and central computer, in
baseline Tomahawk situated in the nose. The aft body is then mounted on
the missile mid-body section. The mid body is split into upper and
lower
halves (containing JP-10 fuel), with a wing stowage space between them.
The pop-out wings pivot at the front of the mid-body ends just forward
of the wings' leading edge and at this point the forward module section
mounts to the above basic airframe.

In the nuclear versions of the missile, the rear half of the
forward module contains a fuel tank, the forward half a W-84 200 kT
tactical nuclear device and the guidance electronics in the nose.
Conventionally armed Tomahawks and MRASMs carry a large WDU-18/B 10001b
HE warhead, as used in the obsolete Bullpup missile, or a submunition
dispensing payload bay. In either instance this is at the expense of
fuel tank volume and results in a major reduction in range. The
immediate nose section in the MRASM houses only the terminal guidance
electronics. In those Tomahawk versions which use TERCOM aided INS for
guidance, the guidance system is common with that of the AGM-86 ALCM.

The ground launched GLCM is the best known of the Tomahawk
family due to both the political upheavals associated with its
deployment and due to staggering program development cost overruns. The
GLCM was conceived in the seventies to enhance the theatre nuclear
strike capability of the USAFE, essentially limited to the F-111 wings
in the UK.

The requirement grew in urgency very rapidly, as the Soviets
deployed the SS-20 Intermediate Range Ballistic Missile, The SS-20 is
essentially a scaled down MIRVed ICBM (some sources suggest it was in
fact derived from an ICBM airframe utilising both the payload, guidance
and upper stages of the original missile), as such it has the
capability
to deliver three Megatonne class nuclear warheads from Western Siberia
to Western Europe, with a respectable CEP (miss distance).

A BGM-109C Ground Launched Cruise Missile bursts out
of its
launcher. The GLCM provides NATO theatre nuclear commanders with a
precise retaliatory weapon capable of striking 1500nm deep into Russian
held territory. Already deployed, it is an effective deterrent to the
Kremlin's SS-20 IRBM strike force which now number nearly 400 units
targeted on Western Europe alone (US Air Force).

The missile is carried on a mobile launcher which is also air
transportable in a C-5 class transport. Without intercontinental range
it is exempt from ICBM limiting treaties and once field deployed out of
its hardened base shelter, is extremely difficult to locate and thus
near impossible to knock out in a pre-emptive strike. With a flight
time
far lesser than that of ICBMs targeted for the US, the SS-20 provides
the Soviet theatre nuclear commander with a very rapid surgical strike
capability against any European target (or if deployed in Vietnam as
suggested by some sources, against any Northern Australian target).

Initial US plans called for deploying single GLCMs towed by
light vehicles, but this soon yielded to the idea of four round
launchers, operated in flights of four launchers. This arrangement was
finally adopted by the USAF. GLCM flights are based each in a hardened
concrete shelter, theoretically impenetrable to conventional PGMs. Each
flight has thus four Transporter Erector Launcher (TEL) units and is
controlled by two Launch Control Centers (LCC).

The TEL is a 56ft (16.9m) semi-trailer, the forward third of
which is an armoured Forward Equipment Box, containing a generator and
launch interface electronics. The remainder of the TEL trailer is then
the hydrauli cally raised four round launcher. The 57ft (17.3m) LCC
trailer is the nerve centre of each GLCM flight. LCCs provide nuclear,
biological, chemical (NBC) protection for the two operators and house
the launch control computers a software target library and HF, VHF,
UHF,
satellite, landline communication equipment.

GLCMs can be targeted and launched only from the LCC, the TEL
electronics allow disarming only. The TELs are tied into their LCCs
with
optical fibre EMP immune cables. Both the TEL and LCC weigh around
80,000 Ib (36 tonnes), both are blast and small arms hardened, both are
air transportable by C-141 and C-5, and both are towed by a common
eight
wheeled 400 HP V-10 10-ton diesel tractor.

Prior to launch the actual launcher is raised and the rear
blast doors opened, the missile is fired from its tube with a 7,000 lbf
class Atlantic Research Corp solid propellant booster, breaking through
a tube cover and climbing until sufficient speed is attained for
wing/control/inlet deployment and engine startup. It then descends to a
programmed altitude, locks on to a heading for its initial TERCOM
matrix
(see Sept TE, ALCM) and follows the characteristic attack profile of
the
TERCOM guided cruise missile, flying from matrix to matrix until its
target is reached, where the W-84 is then airburst at a programmed
altitude. The GLCM has comparable range to the ALCM at 1,500nm (cca
2,500km) but is marginally slower at 485kt against the 530kt of the
ALCM.

In the event of 'increased readiness', the TELs and LCCs
would
deploy out from their shelters, splitting into two groups each with two
TELs and an LCC, and disperse by road to presurveyed launch sites
within
100 miles of the shelter. Opera tionally the weapon has had few of the
TERCOM related problems of the ALCM essentially because the mountainous
terrain of Eastern Europe is unique and well mapped, the biggest
problem
surfacing with the GLCM being the excessive program cost of the order
of
$4,000 million (virtually a whole order of magnitude against initial
estimates).

The GLCM offers an identical mode of deployment to the SS 20
with all of the inherent immunity to a pre-emptive strike (unless of
course a fifth columnist followed the convoy to its dispersal site...),
but compared to an SS-20 it is far inferior in throw weight and
response
time and thus is really no more than a retaliatory deterrent weapon
[Editor's Note 2005: subsequent disclosures identified numerous Russian
civilian participants in the protest movement to be junior Spentznaz
officers].

Even so the Russians are uncomfortable about it, SS-20 is
easily detectable and can be hit (in theory) with Patriot class SAM/ABM
missiles, whereas the GLCM is quite difficult to detect and equally
difficult to hunt down.

With the ability to hit moderately hard targets in the Moscow
area from West European bases the GLCM has quite considerable deterrent
value, the manner in which the Soviets responded to its deployment eg
initiating large scale antinuclear hysteria throughout Western Europe
testifies to this convincingly. The USAF intends to deploy 29 GLCM.
flights in Europe by 1988, most of these based in the UK, Italy and
West
Germany. IOC was attained initially in December, 1983, at Greenham
Common in the UK.

The General Dynamics
RGM-109A/B/C/D SLCM

The SLCM cruise missile family satisfies many of the US
Navy's
diverse surface attack needs. Initial studies for the submarine
launched
Tomahawk began in 1972, the missile first flew in 1976. The weapon was
originally intended for launch from the torpedo tubes of nuclear attack
subs, however the weapon's launching modes and payload/range
characteristics have since diversified. At this stage four launching
modes are anticipated or in use. Torpedo tube launch is currently used
with SSN-637 and SSN-688 class attack subs, but newer 688 class vessels
from 719 on are expected to carry twelve vertical launch tubes in the
forward ballast tanks, freeing space for torpedoes or Harpoon rounds.

Armoured box launchers are currently in use with surface
vessels, the DD-963 class and the Iowa class (eg New Jersey) being
fitted. The DD-963s are to however undergo a future refit, with
Vertical
Launch System (VLS) installations, SLCM/ Harpoon/Standard compatible
with rapid launch/reload capability. The same installation will be used
also on the newer CG-47 class Aegis cruisers. One of the reasons why
the
USN strongly favour the VLS is that it is virtually impossible for a
potential opponent to establish, eg through observation/recce, the
nature of the vessel's weapon mix. Furthermore a failed launcher cannot
disable the weapon system as in eg FFG-7 class vessels.

The SLCM is equipped with the same 7,000 lb launch booster as
the GLCM, the launch sequence is virtually identical aside from torpedo
tube launch where a steel protective shell is discarded upon leaving
the
tube. The nature of the weapon's attack profile will however depend on
the specific type of guidance and warhead fitted.

The RGM-109A TLAM/N (Tomahawk Land Attack Missile/Nuclear) is
virtually equivalent to the USAF GLCM employing both the TERCOM
guidance
and 200kT warhead of the ground launched weapon. Though this missile
was
initially intended to perform a strategic role it was subsequently
decided to the role into theatre nuclear strike and strategic
reserve. As such it would be employed primarily against high value land
targets such as airfields, missile sites and naval installations, the
weapon providing the USN with its desired surgical capability against
post-nuclear exchange targets and with a flexible tool for use in Third
World contingency situations. Significantly it offers the attack sub
fleet a near strategic retaliatory strike capability which due to the
nature of the attack submarine is highly survivable and extremely
flexible. The USN intends to acquire 800 rounds which will arm 32 SSN
class boats and about 100 surface vessels.

The BGM/RGM-109B TASM (Tomahawk Anti Ship Missile) is a
stand-off anti-ship weapon with a conventional warhead. The basic TASM
design employs an inertial midcourse guidance system with a terminal
active radar guidance set modified from the MDC AGM/RGM-84 Harpoon
missile. A 1,000 lb high explosive warhead is employed, this has cut
range down to the 250nm class. TASM performs similarly to Harpoon,
after
launch it will drop to a low cruise altitude and using target
bearing/range data loaded just prior to launch, aim for the immediate
target area. Cruising at a low altitude conceals the location of the
launch vessel. As TASM approaches the target area it will climb steeply
and initiate a target search, flying a preprogrammed pattern. It is at
this stage that the radar seeker is turned on, the previous flight
being
under inertial guidance (strapdown kit). Once the target is located,
TASM locks itself on, drops to a sea skimming altitude and moves in for
the kill, manoeuvring to evade defences and finally punching through
the
side of its victim.

The radar seeker is frequency agile, is credited with the
ability to selectively choose high value targets and may have a home
on-jam capability. The missile has no IFF capability, however. This
aspect of the missile's guidance, together with its considerable
(250nm+) stand-off range and apparently observed difficulties in target
resolution/ECCM have raised a considerable amount of criticism.
Essentially the issue revolves about the all important
rules-of-engagement in surface-surface but particularly
submarine-surface strike situations. The problem lies in acquiring
positive target identification, already limiting the effectiveness of
existing Harpoon this restraint is a big problem with TASM. Suggested
solutions essentially revolve about the use of LAMPS III helos or
orbital radar platforms to provide the launch vessel commander with
Over-The-Horizon (OTH) target data. Another option under review is
ship/sub TASM launch and hand-off to a targeting aircraft (eg P-3). All
of these options really limit the flexibility of the weapon [Editor's
Note 2005: the TASM warstock was later rebuilt into TLAM-C variants as
the targeting issues were never really resolved].

The BGM/RGM-109C TLAM/C (Tomahawk Land Attack
Missile/Conventional) is a non-nuclear precision land attack weapon.
TLAM/C is the heaviest of the SLCM family at 2,8001b, it carries the
large 1,000 Ib warhead of the TASM, the TERCOM/inertial guidance of
TLAM/N and an additional DSMAC II terminal guidance set. DSMAC (Digital
Scene Matching Area Correlator) compares an optical view of the target
area to stored images in the computer memory in order to eliminate the
final TERCOM/inertial errors.

Though the USN have not quoted CEPs for the missiles,
numerous
trial shots illustrate the missiles burying themselves into target
walls
(eg AWST, 20/08/84, p17) or screens (eg Flight 16/10/82, p1113), which
for given warhead size (960 lb) and nominal target hardness would
suggest 15 to 25ft. this pin-point accuracy combined with the missile's
700nm + range suggest its use against high value targets, typically
naval bases (including static shipping), airbases, SAM/ASM launch/C3
installations, command posts and other non-nuclear hardened point
targets.

Current growth capabilities envisaged are a pop-up vertical
attack terminal trajectory for the weapon and also a submunition
dispensing payload bay replacing the HE warhead for airfield attack or
defence suppression. The attack profile resembles that of TLAM/N, with
the exception of the terminal phase when DSMAC provides the final
update.

The SLCM family provide the USN with a very versatile group
of
weapons, particularly the submarine launched land attack missiles offer
an entirely new capability, both in nuclear and conventional warfare.
The USN intends to acquire a total of 4,000 rounds by 1992, IOC was
initially attained in 1983.

The General Dynamics
AGM-109H/L MRASM

MRASM is a low cost air launched derivative of the Tomahawk
family, conventionally armed and intended for both USAF and USN use. As
outlined earlier, the propulsion was changed to a turbojet to cut
costs,
but other measures were also taken. The LN-35 inertial set was replaced
with a low cost strapdown ring laser gyro set, the redundant launch
booster was eliminated and the core weapon guidance (TERCOM/inertial)
relocated to the aft body, freeing the front of the missile for a fully
modular payload bay with terminal guidance only. All versions have 250
nm+ class range, the land attack versions using TERCOM/INS/DSMAC
guidance, the antiship version using datalink midcourse and Imaging
Infra-Red (IIR) terminal guidance.

The AGM-109H is the USAF's airfield attack weapon. It is the
heaviest of the Tomahawk family, at 3,1001b at launch. MRASM is to be
carried primarily by the B-52G and F-16, though other aircraft will be
compatible, and is intended for stand-off counter air or defence
suppression missions. The weapon's forward payload bay is modular,
built
around a 'backbone' beam into which individual payload modules are
plugged into. These modules are tailored to the target, carrying
submunitions such as mines, CEBs (Combined Effects Bomblets) or in
particular, runway attack submunitions (eg BKEP). These are usually
rocket boosted and will punch holes into concrete surfaces or in some
instances penetrate beneath the concrete surface and lift it upon
detonation.

The attack profile is typical, again the launch aircraft
loads
the missile with target particulars, TERCOM matrices and DSMAC scenes,
it then releases the missile within 250nm of the target. The surfaces
and inlet deploy, inertial guidance is activated and the weapon is off
to its first matrix. Upon reaching the target, however, MRASM activates
its Pattern Controller subsystem. This unit uses the exact position
data
provided by DSMAC and flies the missile over the target, eg
runway/taxiway, along a programmed flightpath during which it dispenses
the submuni tion payload in a programmed pattern. As the payload may be
mixed, both surfaces and facilities/aircraft may be attacked and area
denial mines may be also used.

The technique used for expelling munitions from the payload
bay is commonly termed 'air-bag' technology and is simple and robust.
Munitions or clusters of munitions are fixed in the bay with a strap;
this strap has a link in it designed to fail at a certain tensile
loading. An 'air bag' of a high strength fabric (Kevlar?) is placed
beneath the munition, it is tied to the nozzle of a gas generating
cartridge. Upon cartridge ignition the air bag fills with hot gas and
applies an outward force to the munition. At some instant the pressure
in the bag will generate enough force against the munition to break the
link in the strap and the munition is then ejected. Cheap and nasty,
but
cost effective. The DSMAC guidance is credited with night/adverse
weather capability.

Costing about 60% of a baseline Tomahawk, MRASM is
nevertheless an expensive tool, one would therefore expect the USAF to
employ it only in very high density scenarios or perhaps for surprise
counter-air strikes, to lock in enemy aircraft prior to a large scale
air strike with fighter bombers. The modularity of the weapon does
allow
for future upgrades with more advanced submunitions and thus it may
eventually acquire other roles.

The AGM-109L is the USN's air launched weapon and is
configured in two basic versions. The land attack version uses the same
TERCOM/inertial/DSMAC guidance as TLAM/C and also the standard warhead,
the mission profile and type of target are also identical. The
anti-shipping version uses a data-link for midcourse guidance and an
IIR
seeker, modified from the AGM 65D Maverick missile, for terminal
guidance.

The primary launch aircraft is envisaged to be the A-6E
Intruder, though there should be compatibility with other aircraft. The
attack profile for the anti-shipping version is probably unique in the
Tomahawk family, The A-6E would launch at distant targets from
prebriefed data or closer targets from attack radar data, the missile
would then receive datalink updates until within line-of-sight to the
target; after which the seeker would be cued onto the target and a TV
contrast lock engaged to provide a terminal launch-and-leave
capability.
Navy MRASM is shorter and lighter than the USAF weapon, it is easily
recognised by its swept wings in which it is also unique. The weapon
will basically supplement existing Harpoon and also provide a vast
improvement over earlier, eg Walleye, standoff land attack weapons
[Editor's Note 2005: shortly after the publication of this article the
MRASM was cancelled, and soon after the AGM-137 TSSAM program launched.
TSSAM was then cancelled and the AGM-158 JASSM program launched. At
this
time JASSM in is LRIP].

Proposed Tomahawk Applications

The flexibility and modularity of the basic Tomahawk airframe
must be a delight for the weapon system designer. As a result, numerous
other applications for the basic weapon have been proposed. The
strategic anti-shipping or Sea Control role is probably the most
significant. In this role the anti-ship (AF Sea Control) MRASM would be
carried by the B-52, which would serve as a long range patrol aircraft,
using its extensive ESM systems to sniff for enemy shipboard radar and
communication transmissions. It could then attack targets with MRASM
from outside the opponent's air defence umbrella.

Yet another proposal along similar lines envisages the use of
anti-ship SLCM type round, fired from ground based TEL trailers as used
with the GLCM. In this arrangement, the missiles would be targeted at
shipping by their flight LCC as with the GLCM, the LCC would acquire
its
targeting data from aircraft, ships and particularly surveillance
satellites. If using a longer ranged missile such mobile anti-shipping
forces could be airlifted rapidly to key areas, such as Norway,
Iceland,
Turkey, Korea or Japan, to bottle up Soviet battle fleets inside their
home ports, eg Murmansk, Sevastopol, Vladivostok.

During operation, the flights would regularly relocate to
thwart enemy reconnaisance and subsequent air attacks. Another
potential
role for the weapon lies in standoff anti-armour attack, where
typically
a MRASM style weapon would carry autonomously guided anti-armour
submunitions, in the class of the TGSM or Skeet, with tanks costing
over
$1 million apiece it could become eventually cost effective [Editor's
Note 2005: the ground launched TASM never materialised as the Soviet
position began to crumble].

In the context of Australia's force structure the cruise
missile with its strategic flavour definitely appears as a luxury. To
effec tively use any weapon in the class, one really requires extensive
long range surveillance and communication systems, something which is
very much out of the reach of Australia's DoD at this instant [Editor's
Note 2005: long range ISR remains as a major gap in ADF capabilities
twenty years after this was written].

A Sea Launched Cruise Missile emerges from the ocean
depths, launched from the torpedo tube of an attack submarine. The
TLAM/N and TLAM/C land attack cruise missile provides the attack sub
commander with an entirely new offensive capability, be it nuclear
(1500nm) or conventional (700nm). The land attack versions are
complemented by a 250nm + range anti-ship version, all being available
for ship and submarine launch.

Later antiship versions of Tomahawk, hopefully with an OTH
targeting capability using the P-3, could certainly be useful. No
regional powers, excluding Vietnam, really have the sort of air defence
system which would merit the use of MRASM or TLAM/C in preference to a
traditional low level night air strike.

The Soviets are certainly unhappy about the cruise missile
weapon family - it forces them to spend heavily in defensive areas such
as AEW/AWACS and PVO as a whole. With the recent Soviet trend to invest
more in offensive weapons, pouring roubles into expensive (and
expensive
to support) systems which are inherently defensive must be very
unpleasant for Soviet leadership.

As the US holds the lead in key technologies associated with
cruise missile development (propulsion, electronics, stealth) and
anti-cruise missile defences lookdown radar signal processing, IR
planar
arrays) the Soviets can only come out even with inside assistance,
until
then the cruise missile will continue to bleed their resources.

A final point for us to ponder is our future Australian air
defence structure, as deployment of a sub launched TLAM-ski is not that
far away and it will certainly be available on the Third World arms
market in due course. The ultimate implications are more than obvious.

[Editor's Note 2005: while it has
taken two decades for this summary conclusion to materialise in
substance, with regional deployments of 3M-14E, and Chinese equivalents
to the RKV-500/Kh-55M, the substance of the argument holds. Australia's
northern geography is not disimilar to Russian geography in terms of
density and strategic importance.]